Bridging clips have been used for some years in central office and subscriber telephone lines on 66-type connector blocks without hard wiring. Such connector blocks are shown, for example, in U.S. Pat. Nos. 4,053,705, 4,113,340 and 4,126,369. For several years the assignee of the present application, Illinois Tool Works, Inc. of Chicago, Ill. has manufactured bridging clips as shown in U.S. Pat. Nos. Des. 224,405 and 224,406. Audio frequencies representing human speech are carried by such bridging clips in telephone circuits, and noise can be introduced which is annoying and can render the speech difficult to understand if a proper contact is not made. The telephone companies over the years have progressively tightened specifications as to contact resistance on bridging clips, and at the present time a specification of 10 milliohms maximum is in force.
Early bridging clips constructed in accordance with the aforesaid U.S. Pat. Nos. Des. 224,405 and 224,406 generally ran on the order of 10 to 20 milliohms contact resistance. The material in such clips was changed from stainless steel to solder plated phosphor bronze in order to meet temporary specifications. However, this greatly increased the cost of the bridging clips.